Safale S04 overattenuation?

[LuukGx]

Hey guys!
Last tuesday I brewed a Pumpkin Stout that, according to recipe, should've fermented from 1.072 to about 1.018 (lactose added) over the course of a week, using S04. Funny enough, I just took a reading (2 days in) and it's already at 1.014. I'm fermenting under temperature, 19C / 66F, in a controlled environment. Any clues why it took off?

 

[VikeMan]

Have you checked the calibration on your hydrometer?

 

[3 Dawg Night]

I've only used S-04 once, on a milk stout. It didn't over-attenuate for me; in fact, attenuation was right on the money. It was, however, a really fast fermenter! It was done within 48 hours!

 

[Ayzala]

I am wondering the same thing. I just bottled a Smithwick's clone that was supposed to finish at 1.011 and it went all the way down to 1.003 or a 91% attenuation? I'm stumped, oh well my clone will be very dry.

 

[couchsending]

I am wondering the same thing. I just bottled a Smithwick's clone that was supposed to finish at 1.011 and it went all the way down to 1.003 or a 91% attenuation? I'm stumped, oh well my clone will be very dry.

There’s something else at play here. Ever use diastaticus yeast in your fermenters? It’s virtually impossible for 04 to eat all those sugars to get to that level of attenuation.

 

[Ayzala]

I have never used diastaticus yeasts (that I'm aware of), I mainly brew Irish ales, stouts and porters. So S04, S05, Notty and the like. But it's possible I had an infection of wild yeast? I'm brewing a winter warmer this weekend with S05 so I'll see if it happens again.

 

[jobuzo]

Good info, I am learning about the fermentation. I seem to get to about 1.020 on my bears. Just built a ferm chamber and did a pumpkin spice stout and started at 1.050 and in 2 days was at 1.021, now 3 days later only at 1.020.

 

[LuukGx]

There’s something else at play here. Ever use diastaticus yeast in your fermenters? It’s virtually impossible for 04 to eat all those sugars to get to that level of attenuation.

I have but in dedicated fermenters, and the only tool that's used between all is the racking cane (which hasn't touched this beer) and the wine thief (which hadn't touched it till I took this measurement) and they get cleaned and sanitized properly.

 

[LuukGx]

Have you checked the calibration on your hydrometer?

I did just now and it did seem to go a few points under zero with 20C water. Is there a way to re-calibrate?

 

[VikeMan]

I did just now and it did seem to go a few points under zero with 20C water. Is there a way to re-calibrate?

Not unless you can get the paper slip inside to move and then stay put in the right location. I'd recommend getting a new hydrometer. In the meantime, note how far off it is and adjust each reading by that much.

 

[LuukGx]

Yeah it does explain my last two brews reading awkwardly too, even though they seemed closer to what they should've been. Thanks!

 

[day_trippr]

Didn't want to start a thread for this so I'm just going to drop it here. This was the 9th iteration of this imperial-ist stout recipe but this time I really pushed the mash parameters (both grist and temperature profile) to see how far S04 could be taken without resorting to enzymes (glucoamylase, etc). So, lots of low kilned (1.5L) base malt, just enough burnt/charred/roasted malts to fit the style, 148° mash temperature, and 1M cells/ml/°P pitch (on paper, anyway).

The damage was pretty much over in just 10 days

And that's 12.3% ABV and 84.7% attenuation right there. Not too shabby for the strain

Cheers!